1. Field of the Invention
This invention relates to fabrication tools and, particularly, to field-use tools for joining pipe members.
In installing or repairing distribution and delivery systems for fluids, such as heating gas, it is now common practice to utilize polyethylene pipe which is supplied on large rolls. When the pipe is removed from the roll it has a history of being curved so it tends to retain its curved configuration. When it is necessary to join the ends of successive lengths of pipe it is common to use thermo-fusion or, more recently, electro-fusion, a method in which a fitting carrying an electrical heating element is slipped over the joint between the pipe sections to be joined, electrical current is passed through the heating element and the temperature of the junction between the electro-fusion fitting and the pipes to be joined is raised to the temperature where the polyethylene flows and a union occurs between the pipe sections and between the pipe sections and the fitting.
With either thermo-fusion or electro-fusion it is imperative, for a strong joint to be formed, that the ends of the pipe sections being joined, be accurately aligned, i.e. so that the pipe sections are precisely concentric.
Tools and fixtures previously available were not able to achieve that end accurately enough, particularly in the field, where the real need existed. As a result, plastic pipe joints were not reliable and the time consumed in trying to make them reliable was excessive.
Therefore, it is an object of this invention to overcome the various problems of the prior art, as set forth herein-before.
It is a further object of the present invention to provide an alignment tool which is effective, in the field, for producing accurate alignment of plastic pipes, prior to the joining thereof.